Question

The basis of natural selection depends on genetic variation. Please list and explain at least 6 mechanisms for the generation of genetic variation (e.g. how we get new alleles or new allele combinations) within a population.

Answer 1

The mechanisms for the generation of genetic variation are:

1. DNA Rearrangement: Related sequences in the genome may undergo recombination. This leads to the formation of new allele combinations.

2. DNA Acquisition: This is quite common in prokaryotes where they can acquire foreign DNA and they are passed on to the offsprings. This often leads to the emergence of antibiotic resistance species.

3. Transposable elements: Transposons are mobile genetic elements which integrate at specific sites in the genome leading to development of new alleles.

4. Local Sequence Change: Mutations may occur in the DNA sequence of a present allele. This leads to the formation of a new allele which codes for a different protein. This protein might be better than the previous protein encoded, less functional or non functional.

5. Mutagens: These are compounds which induce mutations within the organisms. They may be chemical in nature like 5-bromouracil, acridine, etc or physical mutagens like UV rays, Gamma rays, etc. Exposure to mutagens leads to the formation of new alleles.

6. Gene Flow: It si the flow of genes from one population to the other which leads to genetic variations.